This application is related to Japanese patent applications No. HEI 11(1999)-013657 filed on Jan. 21, 1999 and No. HEI 11(1999)-374377 filed on Dec. 28, 1999 whose priorities are claimed under 35 USC xc2xa7119, the disclosure of which are incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a particle analyzing apparatus for measuring a measurement item of a particle to be analyzed by means of a plurality of measuring parts with different measurement principles.
2. Description of the Related Art
In a particle analyzing apparatus, it is general that measurement is made for a measurement item on the basis of a measurement principle, and its measurement result is displayed. However, in a sample inspection, since samples include both a normal sample and an abnormal sample, it is not necessarily possible to obtain a highly reliable measurement result by a measurement principle. For example, in measurement of the count of platelets, there is no measurement principle capable of providing an accurate measurement result for any samples, and each measurement principle has its merits and demerits.
As systems for individually detecting the count of platelets, there are an electrical detection system and an optical detection system. In an impedance system as a system of the former, electrodes are arranged at both sides of an aperture, and an impedance change generated when a blood cell in an aqueous suspension passes through the aperture is detected. When the blood cell passes through the aperture, a pulse signal in propart to the volume of the blood cell is obtained, and by performing data processing of this pulse signal, the count of platelets and the volume of the platelet can be obtained. In this system, although the platelet is differentiated from an erythrocyte on the basis of its size, where there are fragment erythrocytes, micro erythrocytes, or giant platelets, there is a case where the accurate count of the platelets can not be obtained.
In a flow cytometory system as a system of the latter, scattered light and fluorescence generated when a blood cell in the aqueous suspension passes through an irradiation area of a laser beam is detected by an optical detector. It is possible to obtain a two-dimensional distribution of the detected scattered light and fluorescence. By analyzing this distribution, differentiation of the platelets can be made with high accuracy. That is, distinction from the fragment erythrocytes or the micro erythrocytes becomes easy, and even in the case where there are giant platelets, the count of platelets can be measured. However, since a staining solution is used, there is a sample in which nonspecific staining by the staining solution can be seen, and there is also a case where the count of platelets can not be accurately measured.
There is devised an automatic analyzing apparatus in which measurement of the count of platelets can be made through two systems of the impedance system and the flow cytometory system (Japanese Patent Unexamined Publication No. Hei. 9-508705). According to the apparatus, the count of platelets measured through the flow cytometory system is reported as patient data, and the count of platelets measured through the impedance system is used as a diagnostic tool for monitoring the performance of the apparatus. However, there is no disclosure that comparison is made between the accuracy of platelet measurement based on a measurement principle and that based on another measurement principle, and that the count of platelets having high reliability is provided.
The present invention has been made in view of the foregoing circumstances, and an object of the invention is to provide a particle analyzing apparatus capable of outputting a measurement result with high reliability.
The term xe2x80x9creliabilityxe2x80x9d as referred to in the specification and apended claims means an index for quantitatively reflecting reliance on a certain item.
According to the present invention, there is provided a particle analyzing apparatus comprising a measuring part capable of measuring a specific measurement item of a particle to be analyzed with at least two measurement principles; a judgement processing part for calculating reliability as to at least one measurement principle based on a measurement result in the measuring part and for performing judgement processing of the measurement result in the measuring part based on the calculated reliability; and an output part for outputting the measurement item based on the at least one reliability judged in the judgement processing part.
Here, the at least two measurement principles, for example, include a first measurement principle and a second measurement principle, the first measurement principle is based on an electrical detection system for detecting an electrical change generated when the particle passes through its detection zone, and the second measurement principle is based on an optical detection system for detecting an optical change generated when the particle passes through its detection zone.
The measuring part may be made of one part, or may be made of a plurality of parts. Although the measuring part can measure the specific measurement item of the particle to be analyzed with the at least two measurement principles, only one measurement principle may be actually used.
The judgement processing part may calculate a plurality of reliabilities or may calculates one reliability. Besides, the judgement processing part may set an area which is adjacent to a distribution area of particles to be analyzed in a distribution diagram obtained as a result of measurement in the measuring part and in which any particle does not normally appear. The reliability in this case is, for example, a frequency of appearance of the particles in the area.
The output part may output the measurement item based on a higher (in the case of two) or the highest (in the case of three or more) reliability among the plurality of reliabilities in the judgement processing part, or may output the measurement item based on one reliability in the judgement processing part and may output a definite message or the like.
In the electrical detecting system, it is possible to use an electrical resistance system (impedance system) to detect a resistance change (impedance change) generated when a particle in the aqueous suspension passes through an aperture between two electrodes. As the optical detecting system, it is possible to use a flow cytometory system.
The judgement processing part can be structured by a microcomputer composed of a CPU, ROM, RAM and I/O port, or a personal computer. As the output part, a display device such as a CRT or a liquid crystal display, or a printing device such as a printer can be used.
The particle to be analyzed is, for example, a blood cell component particle such as a platelet, leukocyte, or erythrocyte, a cell in urine, a cultured cell, or a microorganism. The measurement item is, for example, an item as to the count or volume of blood cell component particles such as platelets, leukocytes, or erythrocytes, or an item as to the count or volume of cells in urine, cultured cells, microorganisms, or the like.